Tungsten, molybdenum, rhenium, and niobium, as well as alloys based on each, can exhibit the mechanical properties desired for applications requiring high hardness, optimized compressive strength, and good ductility. Exemplary applications can include, but are not limited to, incandescent light filaments, welding tips, and friction stir welding tools. However, synthesis of powders of these materials exhibiting the appropriate composition and microstructure, is relatively costly and difficult to scale-up. In particular, powders having nano-sized crystallites can be especially challenging to produce on a large scale. Accordingly, a need exists for methods of synthesizing nanocrystalline metal powders of tungsten, molybdenum, rhenium, niobium, or their alloys and for nanocrystalline metal powders having the appropriate mechanical properties.